For investigations in this proposal, expert lymphoma diagnostic skills, immunophenotypic and molecular[unreadable] capabilities, and well-characterized tissue are imperative. Members of the Pathology Core (Core B) will[unreadable] provide the following functions: (1) Pathology Review: Acurate diagnosis of lymphomas will be provided by[unreadable] experienced hematopathologists and molecular pathologists. (2) Tissue banking and distribution: A large[unreadable] number of patient samples are stored, catalogued, and readily retrievable for use in the proposed[unreadable] investigations. The Pathologists will provide selection of appropriate material for the proposed studies from[unreadable] over 15,500 tissue specimens available in our archive. (3) Tissue microarrays (TMA): TMAs are an efficient[unreadable] method for studying protein expression, enabling rapid survey of hundreds of patient samples in a single[unreadable] experiment. TMAs will be used for protein expression studies of newly characterized monoclonal antibodies[unreadable] and novel markers identified by gene expression studies in lymphomas. TMAs will also be used to archive[unreadable] patient samples on an on-going manner as they are accrued into clinical studies described in this proposal.[unreadable] (4) Characterization of new antibodies and testing prognostic models by immunohistochemistry (IHC): IHC[unreadable] with a variety of antibodies with sophisticated methods for their analysis will be provided by members of the[unreadable] Pathology Core. Newly generated antibodies to targets identified by gene expression studies will be[unreadable] characterized using TMAs and IHC techniques.